Calculator Inputs
Example Data Table
| Mass | Volume | Purity | Hydrate Waters | Approx Molarity |
|---|---|---|---|---|
| 13.82 g | 1 L | 100% | 0 | 0.100 M |
| 6.91 g | 500 mL | 100% | 0 | 0.100 M |
| 1.382 g | 100 mL | 99% | 0 | 0.099 M |
| 16.52 g | 1 L | 100% | 1.5 | 0.100 M |
| 69.10 g | 2 L | 98% | 0 | 0.245 M |
Formula Used
The anhydrous molar mass is calculated as:
Molar mass = (2 × K) + C + (3 × O)
Moles = pure mass ÷ molar mass
Molarity = moles ÷ solution volume in liters
Pure mass = weighed mass × purity fraction
Hydrate molar mass = anhydrous molar mass + waters × 18.01528
Required mass = target molarity × target volume × molar mass ÷ purity fraction
Dilution rule = C1 × V1 = C2 × V2
How to Use This Calculator
Enter the weighed potassium carbonate mass and its unit.
Add the final solution volume after dilution.
Set the purity from the chemical label.
Use zero hydrate waters for anhydrous potassium carbonate.
Enter hydrate waters if your reagent is hydrated.
Add target molarity and volume to prepare a planned solution.
Add stock values to solve a dilution plan.
Press Calculate. Review the result above the form.
Use CSV or PDF buttons to save the report.
Potassium Carbonate Molarity Guide
What This Calculator Does
Potassium carbonate is often used in analytical chemistry. It also appears in buffering work. Accurate molarity helps control reactions. This calculator converts a weighed amount into molarity. It also supports preparation planning. You can enter mass, volume, purity, and hydration. The result shows moles and molar concentration. It also reports ionic concentration. Potassium carbonate gives two potassium ions. It gives one carbonate ion. So potassium ion concentration is twice the molarity.
Why Purity Matters
Reagent labels may show less than full purity. Moisture and impurities reduce active compound. The calculator corrects the weighed mass. It multiplies mass by the purity fraction. This gives the pure potassium carbonate mass. That value is then used for moles. This step improves lab accuracy. It is useful for standards and stock solutions.
Hydrate Correction
Some samples contain water of hydration. Hydration increases the formula mass. A larger molar mass means fewer moles per gram. Enter the water number in the hydrate field. Use 1.5 for sesquihydrate material. Use zero for anhydrous powder. You may also enter a custom molar mass. The custom value overrides the automatic value.
Preparation and Dilution
The target section estimates required mass. Enter the desired molarity and final volume. The calculator gives pure mass. It also gives weighed mass after purity correction. The dilution fields use the standard equation. They can estimate final volume from stock. They can also estimate stock volume needed. This helps when preparing weaker solutions.
Practical Notes
Always dry glassware before weighing. Use a balance suitable for your tolerance. Transfer solids carefully. Rinse the weighing container into the flask. Dissolve the solid before final dilution. Bring the solution to the mark. Mix the flask many times. Label the bottle with molarity and date. Record purity, hydrate form, and batch number. Export the result for your worksheet.
FAQs
What is the molar mass of potassium carbonate?
Anhydrous potassium carbonate has an approximate molar mass of 138.2055 g/mol. Hydrated forms have higher molar mass because water molecules are included in the crystal formula.
How do I calculate molarity from grams?
Convert grams to moles by dividing by molar mass. Then divide moles by the final solution volume in liters. Apply purity correction first when the reagent is not fully pure.
What does purity correction mean?
Purity correction estimates the active potassium carbonate mass. A 99% sample means only 0.99 of the weighed mass is treated as actual potassium carbonate.
What should I enter for anhydrous potassium carbonate?
Enter zero in the hydrate waters field. The calculator will use the anhydrous molar mass unless you provide a custom molar mass.
Can this calculate required mass for a target molarity?
Yes. Enter target molarity and target volume. The calculator estimates the pure mass and the actual weighed mass needed after purity correction.
How are potassium ions calculated?
Each potassium carbonate formula unit contains two potassium ions. Therefore, potassium ion concentration equals two times the potassium carbonate molarity.
How is carbonate normality estimated?
For carbonate charge capacity, normality is estimated as two times molarity. This is useful for acid neutralization style calculations.
Can I export the calculation?
Yes. After calculating, use the CSV or PDF button. The export includes inputs and calculated values for records or lab reports.